Problem: Is ${685010}$ divisible by $4$ ?
Explanation: A number is divisible by $4$ if the last two digits are divisible by $4$ . [ Why? We can rewrite the number as a multiple of $100$ plus the last two digits: $ \gray{6850} {10} = \gray{6850} \gray{00} + {10} $ Because $685000$ is a multiple of $100$ , it is also a multiple of $4$ So as long as the value of the last two digits, ${10}$ , is divisible by $4$ , the original number must also be divisible by $4$ Is the value of the last two digits, $10$ , divisible by $4$ No, $10$ is not divisible by $4$, so $685010$ is also not divisible by $4$.